I have a 2000 Prerunner 2.7L. I also have a scanguage and i watched it for 2 years settling between 198 - 202F. even on winters. On real hot days even as high as 207F. The needle would be just at the exact middle or a hair below. Recently, my head gasket blew while coming off the fwy and i had the cylinder head inspected and valves adjusted at the same time.
Since then, after replacing the fluid from green to red. (toyota long life?) My temps have been at 190 to 195F. I did replace my Thermostat too. After all that, I figure that once my temps get to 202F, its time to change the Thermostat and replace my Coolant so i can avert blown headgaskets.
the one good thing is i gained 2mpg from this event...
Hope that helps.